The present invention relates to the use of angiotensin I derivatives, including des-Aspartate angiotensin I in the treatment and/or prevention of infarction-related cardiac injuries and disorders. More particularly, the present invention contemplates a method for the treatment and/or prevention of myocardial infarction, heart failure and/or related conditions. The present invention further contemplates compositions for use in the treatment and/or prophylaxis of infarction-related cardiac injuries and disorders such as but not limited to myocardial infarction and heart failure.
Infarction or necrosis of part of the heart muscle can lead to various conditions including ischemia of cardiac tissue, angina, arrhythmia, cardiac hypertrophy, and heart failure. Extensive infarction or enlargement of infarction may result in cardiac arrest and death. Cardiac or myocardial infarction and related injuries and disorders contribute to significant morbidity and mortality in patients affected by such conditions.
Des-Aspartate angiotensin I (des-Asp-angiotensin I) is a nonapeptide produced from a decapeptide by the action of an aminopeptidase. The nonapeptide is produced from angiotensin I by enzymatic NH2-terminal degradation (1). Des-Asp-angiotensin I is a substrate for plasma and pulmonary angiotensin converting enzyme (2). U.S. Pat. No. 5,773,415 discloses the attenuating effect of des-Asp-angiotensin I on experimentally induced non-infarction-related cardiac hypertrophy in rat. In U.S. Pat. No. 6,100,237, the use of des-Asp-angiotensin I as an anti-neointima and anti-arteriosclerotic agent is disclosed. It appears des-Asp-angiotensin I act on a specific indomethacin and losartan-sensitive subtype of angiotensin receptor AT1 (3) to antagonize the pressor (4) and hypertrophic (5, 6) actions of angiotensin II. AT1 is one of the two specific angiotensin receptors, the activation of which is related to the effect of angiotensin II on cardiac tissue (7).
The level of angiotensin II has been shown to increase after moycardial infarction (7). However, the precise role of angiotensin II in the pathology of myocardial infarction remains to be elucidated.
It has now been found surprisingly that angiotensin I derivatives, including des-Asp-angiotensin I is effective in the treatment and/or prevention of infarction-related cardiac injuries and disorders.
One aspect of the present invention therefore relates to a method for the treatment or prevention of an infarction-related cardiac injury or disorder, the method comprising administering an effective amount of a derivative of angiotensin I to a subject in need of such treatment or prevention. In one embodiment, the derivative of angiotensin I is des-Asp-angiotensin I.
Another aspect of the invention relates to use of a derivative of angiotensin I to treat or prevent an infarction-related cardiac injury or disorder. In another aspect, the invention relates to use of a derivative of angiotensin I in the manufacture of medicament for the treatment or prevention of an infarction-related cardiac injury or disorder. Still a further aspect of the present invention provides a composition comprising a derivative of angiotensin I and a pharmaceutically acceptable carrier for use in the treatment or prevention of an infarction-related cardiac injury or disorder. In another aspect, the present invention relates to a combination comprising a container, a derivative of angiotensin I or a pharmaceutical composition containing the same, and instructions for use of the derivative of angiotensin I or the composition containing the same for the treatment or prevention of an infarction-related cardiac injury or disorder. A kit is also provided which comprises a derivative of angiotensin I and instructions for use of the derivative of angiotensin I for the treatment or prevention of an infarction-related cardiac injury or disorder. In specific embodiments according to these aspects of the invention, the angiotensin I derivative is des-Asp-angiotensin I.
The effect of des-Asp-angiotensin I on the infarct size and transmurality in the left ventricle of a rat following experimental myocardial infarction was determined and the present invention is predicated in part on the determination that a derivative of angiotensin I prevents or otherwise attenuates or decreases the infarct size and transmurality. Animal models for studying infarction-induced injuries and disorders, including small animals such as the rat are well accepted in the art (8). The inventors have therefore determined, surprisingly that a derivative of angiotensin I such as des-Asp-angiotensin I is capable of preventing or otherwise ameliorating infarction-related cardiac injuries and disorders.
Accordingly, one aspect of the present invention provides a method for the treatment and/or prevention of infarction-related injuries and disorders, the method comprising administering an effective amount of a derivative of angiotensin I.
An xe2x80x9ceffective amountxe2x80x9d refers to an amount effective, at dosages and for periods of time necessary to achieve the desired therapeutic result, such as to prevent, inhibit or delay the onset of infarction-related injuries and disorders or ameliorate the symptoms of infarction related injuries and disorders. While the effective amount may vary according to various factors such as the disease state, age, sex, and weight of the individual in the case of a human patient, in one embodiment, the effective amount is about 1.8 mg/kg/day.
The term xe2x80x9cinfarction-related injuries and disordersxe2x80x9d is used herein in its broadest sense and includes myocardial infarction and any and all injuries, disorders or conditions, induced by, following, or related to myocardial infarction, including, ischemia of cardiac tissue, angina, arrhythmia, remodeling cardiac hypertrophy, congestive heart failure, and cardiac arrest. Following infarction, unaffected heart cells will compensate for heart cells that have died by realigning (remodelling) and growing bigger in size (hypertrophy). Remodeling cardiac hypertrophy as that term is used is therefore intended to describe infarction-related hypertrophy and is to be distinguished from non-infarction-related hypertrophy. Persons skilled in the art will also appreciate that treatment of infarction related cardiac hypertrophy differs from the treatment of non-infarction-related cardiac hypertrophy. The former is treated mainly with angiotensin converting enzyme inhibitors such as captopril and angiotensin receptor blockers such as losartan, while any drug that lowers blood pressure may be used to treat non-infarction-related cardiac hypertrophy.
A xe2x80x9cderivative of angiotensin Ixe2x80x9d refers to any mutant, fragment, part or portion of angiotensin I, including molecules comprising single or multiple amino acid substitutions, deletions and/or insertions to angiotensin I and which inhibits, reduces or otherwise interferes with the activity or function of angiotensin II, or homologue, analogue or chemical equivalent thereof which is functionally equivalent in that it inhibits, reduces or otherwise interferes with the activity or functioning of angiotensin II.
Insertional amino acid sequence derivatives are those which include an addition of one or more amino acid residues. The addition may be introduced into a predetermined site or by random insertion with suitable screening of the resulting products. An amino acid insertional derivative of angiotensin I may include amino and/or carboxyl terminal fusions as well as intra-sequence insertions of single or multiple amino acids. Deletional derivatives are characterized by the removal of one or more amino acids from the sequence. Substitutional amino acid derivatives are those in which at least one residue in the sequence has been removed and a different residue inserted in its place.
A homologue of an angiotensin I derivative includes functionally, structurally or stereochemically similar polypeptides, for example from other species, such as livestock animals and laboratory test animals, including rodents and primates.
An analogue of an angiotensin I derivative includes a mimotope, or peptide or analogue mimetic and includes molecules which contain non-naturally occurring amino acids as well as molecules which do not contain amino acids but nevertheless behaves as a functional equivalent. Analogues contemplated herein include modifications to side chains, including deglycosylation or glycosylation, incorporation of unnatural amino acids and/or their derivatives during peptide synthesis and the use of crosslinkers and other methods which impose conformational constraints on the peptide molecule. Analogues also include angiotensin I derivative coupled directly or indirectly to at least one modifying group while retaining the functionality of the derivative. Such modifications are well known in the art and include, for example, a derivative modified to alter a pharmacokinetic property, such as in vivo stability, bioavailability or half-life. The derivative may also be coupled to an additional therapeutic moiety or to a detectable substance.
Examples of unnatural amino acids and/or their derivatives which may be incorporated during peptide synthesis include, but are not limited to, use of norleucine, 4-amino butyric acid, 4-amino-3-hydroxy-5-phenylpentanoic acid, 6-aminohexanoic acid, t-butylglycine, norvaline, phenylglycine, ornithine, sarcosine, 4-amino-3-hydroxy-6-methylheptanoic acid, 2-thienyl alanine and/or D-isomers of amino acids.
Crosslinkers can be used, for example, to stabilize 3D conformations, using homo-bifunctional crosslinkers such as the bifunctional imido esters having (CH2)n spacer groups wherein n=1 to 6, glutaraldehyde, N-hydroxysuccinimide esters and hetero-bifunctional reagents which usually contain an amino-reactive moiety such as N-hydroxysuccinimide and another group specific-reactive moiety.
These types of modifications may be important to stabilize a derivative of angiotensin I, including des-Asp-angiotensin I. This may be important, for example, in the manufacture of a therapeutic composition or if angiotensin I derivative is used in detection assays. Examples of unnatural amino acids that may be incorporated are presented in Table 1.
A chemical equivalent of an angiotensin I derivative shares conformational or functional similarities and may not necessarily be derived from the derivative of angiotensin I. A chemical equivalent may be specifically designed to mimic certain physiochemical properties of a derivative of angiotensin I. Chemical equivalents may be chemically synthesized or may be detected following, for example, natural product screening of candidate compounds which can inhibit, reduce or otherwise interfere with the activity, or functioning of angiotensin II using assays described below.
A derivative of angiotensin I may readily be made using synthetic techniques well known in the art, such as solid phase peptide synthesis and the like, or by recombinant DNA manipulations. Techniques for making substitution mutations at predetermined sites in DNA having known or partially known sequence are well known and include, for example, M13 mutagenesis. The manipulation of DNA sequence to produce variant proteins, which manifest as substitutional, insertional or deletional variants are conveniently described, for example, in Sambrook et al. (9).
A derivative of angiotensin I may be readily identified, for example by its ability to act as an agonist on an indomethacin-sensitive angiotensin receptor or its ability to induce relaxation of a pre-contracted cardiac end of a rabbit pulmonary artery or its ability to attenuate angiotensin II-induced hypertrophy in cultured rat neonatal cardiomyocytes or its ability to attenuate the angiotensin II-induced hyperplasia in cultured rat aortic smooth muscle cells.
A preferred derivative of angiotensin I is des-Asp-angiotensin I, or derivative, homologue, analogue or chemical equivalent thereof. The term derivative in this context has the same meaning as used in the context of angiotensin I as described above. Similarly, the terms homologue, analogue and chemical equivalent as used in this context has the same meaning as described above for angiotensin I derivative generally.
It is well known in the art that modifications and changes can be made to the structure of a peptide without substantially altering the biological function of that peptide. To this end, where des-Asp-angiotensin I is derivatized by amino acid substitution, the amino acids are generally replaced by other amino acids having like properties, such as hydrophobicity, hydrophilicity, electronegativity, size, and the like. Amino acid substitutions are typically of single residues.
Amino acid insertions will usually be in the order of about 1-9 amino acid residues and deletions will range from about 1-9 residues.
Reference herein to angiotensin I derivative and des-Asp-angiotensin I should be read as including reference to all functionally equivalent forms, including, by way of example, isoforms, monomeric, dimeric and multimeric forms.
An effective amount of the derivative of angiotensin I such as but not limited to des-Asp-angiotensin I or a derivative, homologue, analogue or chemical equivalent thereof or a pharmaceutical composition containing the same, as described below, is administered to a subject, such as a human patient, via any acceptable method known in the art, either singly or in combination with other pharmaceutical agents such as captopril or other angiotensin converting enzyme inhibitors or angiotensin receptor antagonists such as losartan. The compound or composition may be administered orally, by suppository, or parenterally (e.g. intramuscularly, intravenously, subcutaneously or intradermally), and in the form of either solid or liquid dosage including tablets, suspensions, or solutions, as is discussed in more detail below. The administration may be conducted in single dosage form with continuous therapy or in single dose therapy ad libitum.
Useful pharmaceutical carriers for the preparation of the pharmaceutical compositions hereof can be solids, liquids or mixtures thereof; thus, the compositions can take the form of tablets, pills, capsules, powders, enterically coated or other protected formulations, sustained release formulations, erodible formulations, implantable devices or components thereof, microsphere formulations, solutions, suspensions, elixirs, aerosols and the like.
Water, saline, aqueous dextrose, and glycols are preferred liquid carriers, particularly (when isotonic) for injectable solutions. The carrier can be selected from various oils including those of petroleum, animal, vegetable or synthetic origin, for example, peanut oil, soybean oil, mineral oil, sesame oil, and the like. Other pharmaceutically acceptable carriers will be apparent to one skilled in the art. Suitable pharmaceutical excipients include starch, cellulose, talc, glucose, lactose, sucrose, gelatin, malt, rice, flour, chalk, silica gel, magnesium stearate, sodium stearate, glycerol monostearate, sodium chloride, dried skim milk, glycerol, propylene glycol, water, ethanol, and the like. The composition may be subjected to conventional pharmaceutical expedients such as sterilization and may contain conventional pharmaceutical additives such as preservatives, stabilizing agents, wetting or emulsifying agents, salts for adjusting osmotic pressure, buffers and the like. Suitable pharmaceutical carriers and their formulations are described in Martin, xe2x80x9cRemington""s Pharmaceutical Sciencesxe2x80x9d, 15th Ed.; Mack Publishing Co., Easton (1975); see, e.g. pp. 1405-1412 and pp 1461-1487. Such compositions will, in general, contain an effective amount of the active compound together with a suitable amount of carrier so as to prepare the proper dosage form for proper administration to the host.
The methods of the present invention may be practiced when the relief of symptoms is specifically required or to prevent imminent threat of an infarction related cardiac injury or disorder. For example, angina that occurs at rest can indicate an imminent myocardial infarction and administration of angiotensin I derivative such as des-Asp-angiotensin to a person experiencing such symptom may prevent myocardical infarction in that patient. The method of the invention may also be effectively practiced as a continuous or prophylactic treatment.
In the practice of the therapeutic methods of the invention, the particular dosage of pharmaceutical composition to be administered to the subject will depend on a variety of consideration including the stage of the disease or condition, the severity thereof, the schedule of administration, the age and physical characteristics of the subject, and so forth. Proper dosages may be established using clinical approaches familiar to the medicinal arts.
An angiotensin I derivative, including des-Asp-angiotensin I or a pharmaceutical composition containing the same may be provided, sold or otherwise made available, including to patients, physicians and pharmacists, in a container together with instructions for use of the derivative or composition in the treatment or prevention of an infarction related cardiac injury or disorder. One aspect of the invention therefore relates to any such combination. It will be understood that the container in any such combination will be suitable for storing the derivative of angiotensin I or the composition containing the same. Another aspect of the invention relates to a kit comprising a derivative of angiotensin I and instructions for use of the derivative of angiotensin I for the treatment or prevention of an infarction related cardiac injury or disorder. In one embodiment, the kit may further include a pharmaceutically acceptable carrier. In different embodiments of these aspects of the invention, the derivative of angiotensin I may be des-Asp-angiotensin I or derivative, homologue, analogue or chemical equivalent thereof.
Although the present invention is particularly exemplified herein in relation to rats, it is understood that the present invention extends to the use of angiotensin I derivatives in any mammal subject including, but not limited to, humans, mice, rabbits, livestock animals and primates.
The present invention is further described in the following non-limiting Examples.